Not applicable.
Not Applicable.
The invention relates to a knotless suture anchor system for attaching soft tissue to hard bone, and to methods for attaching soft tissue to hard bone.
Soft tissues, such as ligaments, tendons and muscles, are attached to a large portion of the human skeleton. In particular, many ligaments and tendons are attached to the bones which form joints, such as shoulder and knee joints. A variety of injuries and conditions require attachment or reattachment of a soft tissue to bone. For example, when otherwise healthy tissue has been torn away from a bone, surgery is often required to reattach the tissue to the bone to allow healing and a natural reattachment to occur.
A number of devices and methods have been developed to attach soft tissue to bone. These include screws, staples, cement, suture anchors, and sutures alone. Some of the more successful methods involve use of a suture anchor to attach a suture to the bone, and tying the suture in a manner that holds the tissue in close proximity to the bone.
The tissue may be attached to the bone during open surgery, or during closed (e.g., arthroscopic) surgical procedures. Closed surgical procedures are preferred since they are less invasive and are less likely to cause patient trauma. In a closed surgical procedure, the surgeon performs diagnostic and therapeutic procedures at the surgical site through small incisions, called portals, using instruments specially designed for this purpose. One problem encountered in the less invasive, closed surgical procedures is that the surgeon has significantly less room to perform the required manipulations at the surgical site. Thus, devices and methods are needed which will allow a surgeon to effectively and easily attach tissue to bone in the small spaces provided by less invasive surgical procedures.
Conventional methods for attaching soft tissue to bone typically require that the surgeon tie a knot in the suture thread to attach the suture to an anchor, or to attach the tissue to the bone using the suture. Knot tying at the surgical site in closed surgical procedures, and even in open surgery, is difficult and time consuming due to inherent space constraints. Further, knots and other bulky attachment means can irritate tissue over time.
Knotless suture anchor systems have been developed for use with closed surgical procedures, and U.S. Pat. No. 5,569,306 provides one example of such a system. A further knotless suture anchor and system is disclosed in U.S. Pat. No. 5,782,864. Although generally useful, such systems can be limited to use only with certain types or shapes of tissue, or to use with certain anatomical structures. Proper attachment of soft tissue requires that it be placed in the anatomically correct position to promote optimal healing.
Further, some conventional knotless suture anchor systems may require, in order to attach a broader array of tissue shapes to bone, that the suture anchor pass though the tissue to be attached. This is undesirable because it unnecessarily irritates the injured tissue and it requires opening a much larger hole in the tissue.
There is thus a need for an improved system for anchoring soft tissue to bone which reduces or eliminates the need to tie suture knots at the surgical site. Further, there is a need for an improved system for anchoring soft tissue to hard bone which is easy and fast to deploy and requires few tools. It would also be advantageous to provide a fully absorbable knotless suture anchor and system.
The present invention provides a system for anchoring tissue to bone including a suture anchor, a first suture loop attached to the suture anchor, a suture needle and a second suture loop attached to the suture needle and interlocked with the first suture loop. The second suture loop may be formed by attaching two free ends of a length of suture thread directly to the suture needle, or by attaching the two free ends within a suture closure which may then be attached to the suture needle. In a preferred embodiment, the suture anchor is entirely bioabsorbable. A method is also provided by which a detached tissue may be securely attached to bone in an anatomically correct position without the need to tie a knot.
In an exemplary embodiment, the system includes a suture anchor having a first, leading end, a second, trailing end, and two opposed sides between the first and second ends. The second end has a flared portion that renders the suture anchor asymmetrical in a plane that includes the longitudinal axis. The first suture loop is attached at a position between the first and second ends of the suture anchor and is interlocked with the second suture loop. The second suture loop is attached to a trailing end of the suture needle. The asymmetrical shape of the suture anchor assists in securing the anchor within bone. When tension and deflection by the inserter is applied to the suture anchor, after the anchor is positioned within bone, the anchor undergoes a toggling action, or rotation which results in the anchor being oriented in a direction that is not parallel with the longitudinal axis of the anchor-seating bore. This toggling of the anchor causes the anchor to become lodged within the bone. Thus, the anchor can be firmly embedded within bone without the need for ancillary anchoring structure such as arcs.
In an embodiment that is particulary useful in closed surgery, the second suture loop is formed using a suture loop closure and is attached to a hollow suture needle by means of a slot provided in a wall of the hollow needle. This embodiment may also employ an actuator, disposed within the hollow needle, which can be selectively deployed to disengage the second suture loop from the needle. The hollow needle used with this embodiment preferably is part of an elongate tool, such as a suture inserter, that is useful in closed surgical procedures. The hollow needle typically forms the distal end of such a tool.
The system may be used in a method wherein the suture needle and the attached second suture loop are passed through a detached segment of tissue. The second suture loop is pulled through the detached tissue until a portion of the interlocked first suture portion of the first suture loop is seated within a suture thread-engaging groove at the first end of the anchor. The anchor is then tapped into a predrilled bore in a portion of hard bone. Once inside the bone, tension is applied to the anchor by sutures, causing the anchor to toggle such that it is no longer oriented in a direction parallel to the longitudinal axis of the bore, and the flared portion of the anchor engages and is wedged into the wall of the bore. The suture anchor is thus stabilized in an interference fit within the bore, and the detached tissue is thereby attached to the bone in the desired position.
The term xe2x80x9csuture needlexe2x80x9d is used herein to encompass both conventional suture needles, used in open surgical procedures, as well as suture needles that may form a hollow, distal end of an elongate tool useful with closed surgical procedures.
Further features of the invention, its nature and various advantages, will be more apparent from the accompanying drawings and the following detailed description of the drawings and the preferred embodiments.